Topband: ground radial corrosion

[N7DF]

when I was in Guam the corrosion rate on any metal in contact with the ground, water or any other metal was so high that I had to resort to connecting sacrificial anodes to just about everything.  The cause was an extremely acidic environment caused by acid rain from offshore volcanic gases.
 
As long as the anode is a more reactive metal than the material being protected corrosion will be practically eliminated
 
for iron and copper, zinc anodes are sufficient but for galvanized surfaces and aluminum you need to use magnesium anodes
 
just make sure that all metal objects to be protected are tightly connected together with wire that is less chemically reactive than the object and then the wire connected to the anode which is buried in the ground.  Usually solid, soft drawn copper is the best.  If the soil is very acidic you might need silver wire, (silver solder can also be used).
 
Over time the anode will erode away and need replacement.
 
You may actually see metal plating out from the soil onto iron or galvanized surfaces.  This will be aluminum from clay particles in the soil and will appear as soft, hairlike filaments where the metal touches the ground.